Phase II Evaluation of Oral Estramustine, Oral Etoposide, and Intravenous Paclitaxel in Patients with Hormone-Sensitive Prostate Adenocarcinoma

Abstract Purpose The primary objective of this study was to assess the feasibility and efficacy of administering etoposide/estramustine/paclitaxel in hormone-sensitive metastatic prostate cancer responding to hormonal therapy. Patients and Methods Eligible patients had metastatic prostate cancer and had received combined androgen blockade for 6-8 months with a ≤ 80% decrease in prostate-specific antigen from pretreatment. They received 4 cycles of chemotherapy consisting of estramustine 280 mg orally 3 times daily, etoposide 50 mg/m2 orally on days 1-14, and paclitaxel 135 mg/m2 intravenously for 1 hour on day 2 of each 21-day cycle and were then followed until time to treatment failure (TTF). Results Twenty-six patients were evaluable for response and toxicity. Median TTF was 21.7 months (range, 11.9-64.5 months; 95% confidence interval, 15.3-26.2 months). Median survival from time of initiation of hormone therapy was 5.1 years. Neutropenia was the most common grade 3/4 toxicity, occurring in 3 patients. Significant toxicities were limited to nausea, diarrhea, and febrile neutropenia in 3 patients, respectively. Conclusion The administration of paclitaxel/estramustine/etoposide in this setting is feasible and well tolerated. Although the TTF of 21.7 months by prostate-specific antigen criteria is similar to historical controls in the emergence of clinically evident androgen-independent disease after starting hormone therapy, direct comparisons cannot be made. More trials are needed to investigate the timing of chemotherapy in patients with prostate cancer.